It is often necessary to surgically correct and stabilize spinal curvatures, or to facilitate spinal fusion, for example as the result of a degenerative spinal disorder such as scoliosis. Numerous systems for use in spinal correction and fixation have been disclosed. These systems usually include a pair of elongated members, typically either rods or plates, longitudinally placed on the posterior spine on either side of spinous processes of the vertebral column. For the sake of simplicity, the term “rod” will be used hereafter to refer to any elongated member regardless of size and/or shape. Each rod is attached to various vertebra along the length of the spine by way of attachment devices which may include, but are not limited to, pedicle screws, plates, transverse process hooks, sublaminar hooks, pedicle hooks, clamps, wire, etc.
It is also well known that the strength and stability of such dual rod assemblies can be increased by coupling the two rods with a cross-brace or transconnector which extends substantially horizontally across the spine to connect the longitudinal spinal rods. The use of transconnectors, however, can provide surgeons with one or more difficulties. First, the simplest situation in which a transconnector could be used occurs when the two rods are parallel to each other, i.e. there is no rod convergence or divergence in the medial-lateral direction; where the two rods have the same orientation with respect to the coronal plane viewed in the anterior-posterior direction, i.e. the rods are coplanar from a lateral view; and where the two rods are located at a fixed, predetermined distance from each other. However, due to a wide variety of factors, the two rods are rarely so geometrically aligned in clinical situations.
Thus, it is advantageous to provide a transconnector which may be adjusted to adapt to variations in spinal rod alignment. The addition of such adjustability, however, may require the transconnector to consist of numerous pieces that can be difficult to assemble and use while in the surgical environment.
Furthermore, when transconnectors are placed over adjacent spinal rods, the extended profile of the device often results in soft tissue trauma and may result in surgical complications. Thus, it is advantageous to provide a transconnector with as small a lateral (i.e., transverse) profile as possible to decrease the total amount of soft tissue trauma incurred, and to minimize the chance for subsequent complications.
It is further advantageous to provide a transconnector that, once assembled, prevents disassembly of the individual pieces of the transconnector assembly, thereby helping to facilitate installation of the transconnector by reducing the likelihood that the transconnector will accidentally come apart during installation in the patient. It is also advantageous to provide a transconnector that reduces the overall number of steps required to fix the location of the transconnector with respect to the longitudinal spinal rods, thereby facilitating installation of the transconnector by reducing the time and effort needed for installation in the patient.
Thus, there exists a need for an improved transconnector for coupling adjacent spinal rods which advantageously may be adapted to adjust to varying spinal rod alignments, which has a reduced lateral footprint for reducing associated tissue trauma and which when pre-assembled will remain in tact during installation in the patient.